It may have started with the death of a cow on a farm in Pitsham, West Sussex, England, in 1984 – two years before "mad cow disease" was officially identified. It ended by changing the way the UK approaches farming, prepares food, conducts surgery and gives blood.

BSE's unheralded arrival in the UK – it might have in fact existed since the 1970s at such a low level that farmers and vets did not notice it – was to wreak havoc in agriculture, undermine trust in government and sour international relations. The linked human disease, called variant CJD, or "the British disease" in some quarters, has caused the lingering deaths of 176 Britons and nearly 50 others around the world, including three in the US. The whole episode has cost the British taxpayers billions.

The health department played down the issue at an early stage. But it was one of Gummer's predecessors, John MacGregor, who took what in retrospect was the key protective measure on limiting the spread to humans by banning risky parts of cattle (including brain and spinal cord) from entering the food chain when the crisis erupted. He overrode the advice of his civil servants in private, but then he also downplayed the importance in public.

By the time the first UK death from the horrific, long-incubating vCJD – that of 19-year-old Stephen Churchill – occurred in 1995, with the bombshell of a possible link to BSE announced in March the following year, the peak of BSE infection in cattle had passed. The disease was in retreat, thanks to a ban on feeding the meat and bone meal that had passed on the infection from dead cattle to live ones.

The worst years for cattle deaths from BSE in England, Scotland and Wales, was 1992 (36,680) and 1993 (34,370). But millions of other cows have been destroyed because they were too old to go into human or animal food.

In the years that followed, widely varying forecasts of the human death toll from vCJD in the UK were made. Those that predicted fewer than 100 deaths proved far too optimistic. Those that predicted a six-figure toll may look to some over-pessimistic. Three British cases have been linked to blood transfusion involving infected donors.

Some believe the crisis in the UK is almost over and restrictions on cattle allowed to enter the food chain have been eased substantially in recent years. All are tested. Fears of BSE-like diseases in other species – most notably sheep and goats – have led to better controls and monitoring of them too. Others are more cautious, particularly over whether vCJD has indeed been consigned to history.

The crisis changed for ever official estimate of risk. Years of lax controls, poor oversight of slaughterhouse practices and political complacency, then secrecy, changed attitudes among civil servants and politicians. They are now more ready to consider worst-case scenarios – critics would say too ready.

The BSE inquiry, set up by Tony Blair early in office, though long, detailed and complicated, was held in public. Now Britons are hardly surprised by the grilling of ministers and key players, for example in the current Leveson dissection of the media, its practices and links with politicians.

Governments are less tempted to ignore scientific advice. Civil servants were urged by the BSE inquiry to be less ready to sit on bad news. Ministers, bruised by the experience of BSE and other public health disasters such as salmonella in eggs in the 1990s, are more open on public health risks. The public now expects government to be straight with them about the risks.